Planet
, a typical example of a planet.]] A planet is a celestial object that orbits a star. Many planets have their own name, but the Tau'ri also assign designations, which are based on binary codes for the use of extrapolation. A terrestrial planet is distinct from a gas giant or a moon in that it has a solid surface and orbits a star, not another planet or gas giant. Milky Way planets are usually designated with P??-???, Pegasus planets are M??-???, planets in NGC 3109 are designated O??-???, whilst planets in the Vennix Galaxy are usually designated with V??-???. Planet classification Temperate , a temperate-"forest"-class planet.]] "Temperate planets" are by the far one of the most common planet types in the known universe and are the most hospitable for human life. They are often referred to as "Earth-like planets" by the Tau'ri, after their homeworld, which, for many centuries, was considered the only location of life in the universe. The biome of temperate planets typically varies between desert, arctic and all variations in between although the vast majority of temperate planets are single-biome environments consisting of either forest, jungle or grassland – speculated to be due to the Ancients' terraforming efforts. Such worlds are often referred to as "forest", "jungle", or "savannah" planets. Gas giant , a gas giant.]] A "gas giant" is a type of planet, consisting primarily of just gases, and contain little rock or other solid matter except for the core. Gas giants make up some up some of the largest planets encountered by the Tau'ri. Although they cannot support human life, however some may have moons in orbit which are habitable and can hold Stargates. Terrestrial "Terrestrial planets" are planets composed primarily of silicate rocks or metals, such as the four inner planets of the Sol system; Mercury, Venus, Earth, and Mars. Terrestrial planets all have approximately the same type of structure: a central metallic core, mostly iron, with a surrounding silicate mantle. Most other planet types, bar gas giants, are terrestrial planets, however they are typically referred to by their primary classification, with worlds such as Mercury, Venus or Adara II being referred to as "uninhabitable planets", due to their high surface temperatures or dense atmospheres, making them inhospitable for humanoid life. Desert , sometimes classified as a desert planet.]] A "desert planet" is a single-biome planet on which the climate is mostly desert, with little or no natural precipitation. Desert planets are fairly common in the known universe; Dakara and Mars are often considered prime examples. Indeed, many terrestrial planets would be considered desert planets by this definition. However, the term is often used to refer to desert planets that remain hospitable for human life. Icarus-type , an Icarus-type desert planet before its destruction in 2009.]] An "Icarus-type planet" is a unique class of terrestrial planet in that the only criteria is the prescence of a radioactive Naquadria core, making the surface conditions of these planets extremely variable. As such Icarus-type planets are exceedingly rare, and are typically only found at Ancient or Goa'uld test sites. There are only four known Icarus-type planets, P4X-351, the Lucian Alliance outpost planet (both of which were destroyed during attempts to dial the Ninth chevron), Langara and Arcturus VII. Ice ; an ice planet in the Vennix Galaxy.]] An "ice planet" is a terrestrial planet whose surface is predominantly covered by ice or snow, perhaps with a small tundra/subarctic region surrounding the equator. A lot of ice planets could have subsurface oceans, warmed by their cores and tidal forces from another nearby body. If there is liquid water beneath the icy crust, there could be life, including fish, plankton, and microorganisms. V9X-632 is an ice planet located in the Vennix Galaxy, and although this class of planet is believed to fairly common throughout the universe, due to their inhospitable environment, it is rare for them to have a Stargate. Oceanic An "oceanic planet" (also termed a waterworld) is a type of planet whose surface is completely covered with an ocean of water. The oceans on such planets would be hundreds of kilometers deep, much deeper than the oceans of Earth, punctuated only by island chains formed by undersea mountain ridges or volcanos. Both Lantea and New Lantea are prominent ocean planets, with the former only possessing a land area of 15 million square miles, covering about 7% of the planet's surface. Lists *Off the grid planet *List of planets **Milky Way Galaxy Planets **Pegasus Galaxy Planets **Vennix Galaxy Planets External links * * Category:Celestial bodies